In the co-pending application of John G. Stevenson, Ser. No. 08/236,800, filed May 2, 1994, now U.S. Pat. No. 5,566,880 and assigned to applicants' assignee, a system is described in which a path test command is launched in a network, following a path determined in the same way as a normal data transfer from a source to a destination in a so-called connectionless network, that is, in a network in which the transmission path is not predetermined prior to the transmission of data. At each node encountered along the connection path, the path test command initiates a path test identifying that node and the current time. These results of the path test are sent back to the node initiating the path test command. Thus, as the path test command traverses the data path, a sequence of test results flow from each of the nodes encountered along the path back to the originating node. As noted in the aforementioned patent application, these results can be combined at the originating node to determine the response time of the entire path from source to destination, the response time of each leg along this path, and hence the identification of congestion points in the path. If the destination node is never reached, the returned test results serve to identify the first encountered failed transmission leg or node. This testing approach has the advantage of being useful with connectionless networks as well as pre-calculated routing protocol path networks. This testing approach has the disadvantage, however, of requiring each and every resource in the network to be modified so as to be responsive to the path test command.
Another route testing technique is disclosed in T. Hefel et al. application Ser. No. filed 08/500,674, filed Jul. 10, 1995, now U.S. Pat. No. 5,563,875 also assigned to applicants' assignee, in which a source node launches a plurality of wrap around test messages, one for each node in the path between the source node and the destination node. Each message includes a launching time which can be used to determine the round trip transit time to the corresponding intermediate (and destination) node and thus the link delay times. As with the previous application Ser. No. 08/236,800, these times can be used to determine link or node failures, congestion points and route performance. Although this latter test method requires no changes in the network except at the wrap around test source, it has the disadvantage of being useful only with pre-calculated route protocol paths.
Packet switching networks normally have a network supervisor who is responsible for the overall management of the network. In order to manage the route testing function from a central location, it is necessary to initiate, and to ascertain the results of, path tests from a central location. The most common control command mechanism available for managing packet networks is known as the Simple Network Management Protocol (SNMP). In the SNMP system, a simple "GET" or "GET.sub.-- NEXT" command is used to obtain a single stored value from a remote node in the packet network. Similarly, a simple "SET" command is used to set a single value in a remote node of the packet network. Unfortunately, this simple command structure does not lend itself well to obtaining the detailed results of the path tests necessary for centralized test management. In the prior art systems utilizing such a limited command structure, it is difficult or impossible to centrally manage the route tests for the entire packet transmission system. Without central management, each node must manage all of the tests originating at that node, requiring duplication of the test management facilities at each of the nodes, thereby increasing the cost and complexity and reducing the throughput of the network.